Takahiro Yabe

Inflation and Peel-off Characteristics of MLI Blanket under Depressurization Environment

The inflation and peel-off characteristics of a multilayer insulation (MLI) blanket under a depressurization environment have been evaluated for establishing a JAXA design standard. The venting conductance of gas flow from inside to the outside of MLI was evaluated in a steady state test, and was confirmed to take a value of the same level regardless of shape or size or pressure level when having the same perforation, spacer type, and attachment specification. In the depressurization test, MLI was observed as not inflating in a region of higher pressure even at higher depressurization speed, while inflating in a lower pressure region. The differential pressure between the inside and outside of MLI peaks when the level of pressure drops to about one kilo pascal or less. In addition, a simple mathmatical model of MLI inflation and venting is constructed and numerical simulations based on the model are conducted, which indicate that depressurization ratio (depressurization speed per the level of pressure) and volume of MLI are the dominant parameters.

Characteristics of Reservoir Embedded Loop Heat Pipe in Deployable Radiator on ETS-VIII at Beginning of the Experiment under Orbital Environment

A deployable radiator (DPR) on the Engineering Test Satellite-VIII (ETS-VIII) was launched to a geo stationary orbit using H-IIA rocket on 18 Dec. 2006, carrying a deployable radiator (DPR). Deployable radiators are anticipated for extension of the radiator area on satellites to mitigate increased heat generation. The DPR is an experimental apparatus on the ETSVIII; it has a reservoir-embedded loop heat pipe (RELHP) for heat transfer from the experimental heat load to the DPR radiator. The RELHP reservoir is embedded in the evaporator for reliable function of the Loop Heat Pipe (LHP). This paper describes the DPR and the RELHP characteristics on the ETS-VIII from its launch operation to the beginning of the test under an orbital environment.